Plaques on dorsal hands & arms

Differential Dx includes BCC and sarcoidosis

Superficial basal cell carcinoma (BCC).³ Like chromoblastomycosis, BCC has a similar history of slow-growing scaly plaques. With BCC, there is usually a solitary plaque, although it may be large. Biopsy would distinguish BCC from chromoblastomycosis.

Sarcoidosis.^3,4 The plaques of sarcoidosis are less scaly than those of chromoblastomycosis and biopsy would show granulomatous process. Sarcoidosis may also be associated with respiratory symptoms, elevated angiotensin converting enzyme, or hilar nodules on chest x-ray.

Plaque-type porokeratosis.⁴ Porokera-tosis is an inherited or acquired solitary lesion that is annular, round, and thin with raised edges; it often develops on the lower legs. What triggers its appearance is unknown, though trauma and photodamage have been suggested. In some variants, it may appear similar to chromoblastomycosis.

Cellulitis. In cellulitis, the advancing edge of erythema changes over days instead of months to years (as chromoblastomycosis does). Possible systemic symptoms of cellulitis include pain, fever, swelling, or malaise.

Cutaneous tuberculosis.³ Although rare, cutaneous tuberculosis, which often presents as firm, shallow ulcers with a granular base, may be associated with significant discomfort. It can persist for up to a year, is more likely to form an abscess and drain, and is associated with lymphadenopathy after several weeks.

Sporotrichosis.³ The appearance of sporotrichosis is similar to that of chromoblastomycosis, with hematogenous spread that may mimic autoinoculation. Biopsy and tissue culture would differentiate sporotrichosis from chromoblastomycosis.